High Availability Clustering (EX436)

This exam is based on Red Hat Enterprise Linux 7.

Study Points for the EX436 Exam

Candidates should be able to perform the tasks listed below:

  1. Configure a high-availability cluster, using either physical or virtual systems, that:
    1. Utilises shared storage
    2. Provides service fail-over between the cluster nodes
    3. Provides preferred node for a given service
    4. Selectively fails over services based on specific constraints
    5. Preemptively removes non-functioning cluster members to prevent corruption of shared storage
  2. Manage logical volumes in a clustered environment:
    1. Create volume groups that are available to all members of a highly available cluster
    2. Create logical volumes that can be simultaneously mounted by all members of a high-availability cluster
  3. Configure a GFS file system to meet specified size, layout, and performance objectives
  4. Configure iSCSI initiators
  5. Use multipathed devices
  6. Configure cluster logging
  7. Configure cluster monitoring

As with all Red Hat performance-based exams, configurations must persist after reboot without intervention.

Red Hat Docs and Study Material

Red Hat Certificate of Expertise in High Availability Clustering (EX436)

High Availability Add-On Overview on RHEL 7 (PDF)
High Availability Add-On Administration on RHEL 7 (PDF)
High Availability Add-On Reference on RHEL 7 (PDF)
Global File System 2 (PDF)

Other Study Material

Sander van Vugt has released a book for “Pro Linux High Availability Clustering“. Check it out.

There is also a “Linux High Availability Clustering Complete Video Course” available that covers EX436 objectives.

Red Hat Enterprise Linux Developer Suite

You may find the RHEL Developer Suite subscription helpful for developing high availability clustering skills.

The Red Hat Enterprise Linux Developer Suite subscription is available at no cost by registering with the Red Hat Developers Program.

The Red Hat Enterprise Linux Developer Suite Subscription is a self-support option for application development. It includes Red Hat Enterprise Linux, High Availability Add-On, Load Balancer Add-On, Resilient Storage Add-On, Scalable File Systems Add-On, High Performance Network Add-On, Extended Update Support Add-on, Smart Management, and Real Time operating system. This subscription is for development purposes only.

The subscription also provides access to the valuable Red Hat knowledgebase, forums and updates.

4 thoughts on “EX436

  1. Hello,

    I’m trying to set up a lab with 1 target server and 2 initiators clients, each client having 2 network interfaces on different networks then I can test multipathing.
    My problem is that when I disconnect the dedicated interfaces, it starts using the default interface, which is configured with a default gateway. How to configure these dedicated interfaces then when they are switched off, it will not use the default gateway ? I’ve seen plenty of tutorials with routing options that don’t seem to work for my need.


    • You need 3 interfaces, where two are non-routable vlans for iSCSI traffic. When you do an iSCSI discovery, use both of the iSCSI vlans. You can also set path_grouping_policy to failover. When both iSCSI paths are down, the storage should no longer be accessible.

      [[email protected] ~]# multipath -ll
      mpatha (36001405688c3235427e49e48d0f04745) dm-2 LIO-ORG ,block1          
      size=1.0G features='0' hwhandler='0' wp=rw
      |-+- policy='service-time 0' prio=0 status=active
      | `- 2:0:0:0 sda 8:0  active faulty offline
      `-+- policy='service-time 0' prio=0 status=enabled
        `- 3:0:0:0 sdb 8:16 active faulty offline

      Journal entries:

      multipathd[14175]: mpatha: sda - path offline
      multipathd[14175]: mpatha: sdb - path offline

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